The present invention relates to the production of oxygenated fuels. Specifically, the invention relates to the removal of excess residual water from an oxygenated fuel composition comprising isopropanol and gasoline.
There is a great need to produce high-octane gasoline. However, the use of the traditional lead-containing gasoline additives has been largely discontinued. So, oxygenated compounds such as ethanol, isopropanol and methyl-t-butyl ether which are high-octane components are now finding their way into the motor gasoline pool.
In making alcohols, particularly, isopropanol, by the direct hydration of olefins, the raw product from the hydration reactor generally contains a substantial quantity of water in addition to the alcohol. Dehydration of the aqueous alcoholic solution has generally required energy intensive procedures such as extractive distillation or azeotropic distillation.
In my U.S. applications entitled "Extractive Blending Process," "Continuous Extractive Blending Process" and "Improved Extractive Blending Process," filed concurrently herewith and incorporated by reference herein, are disclosed processes for simultaneously removing alcohols from aqueous solutions and blending them with a gasoline blending hydrocarbon component. Even when using these methods, there is sometimes too much water left in the resulting alcohol-gasoline blend. The present invention provides a process for dehydrating such alcohol-gasoline blends, particularly isopropanol-gasoline blends, produced by extractive blending or any other methods.